Based on this review, there is weak evidence that older age and history of sickness absence are factors associated with long-term sick leave in sick-listed employees. There is insufficient evidence for an effect of other individual or work-related factors on long-term sick leave. There are no published studies on perpetuating factors related to long-term sick leave.

Besides sickness, several non-medical factors are recognized barriers for return to work. Factors such as illness perceptions and self-efficacy expectations are reported to be promoting factors for return to work.

PurposeTo reach insurance physician (IPs) consensus on factors that must be taken into account in the assessment of the work ability of employees who are sick-listed for 2 years.MethodsA Delphi study using online questionnaires was conducted from October 2010 to March 2011.ResultsOne hundred and two insurance physicians reached a consensus on important factors for return to work (RTW) of employees on long-term sick leave; from those factors, the most relevant for the assessment of work ability was determined. From a total of 22 relevant factors considered for the return to work of long-term sick-listed employees, consensus was reached on nine relevant factors that need to be taken into account in the assessment of the work ability of employees on long-term sick leave. Relevant factors that support return to work are motivation, attitude towards RTW, assessment of cognitions and behaviour, vocational rehabilitation in an early stage and instruction for the sick-listed employee to cope with his disabilities. Relevant factors that hinder RTW are secondary gain from illness, negative perceptions of illness, inefficient coping style and incorrect advice of treating physicians regarding RTW.ConclusionsNon-medical personal and environmental factors may either hinder or promote RTW and must be considered in the assessment of the work ability of long-term sick-listed employees. Assessment of work ability should start early during the sick leave period. These factors may be used by IPs to improve the quality of the assessment of the work ability of employees on long-term sick leave.